The new experiment, the JLab Eta Factory (JEF), in the experimental Hall D
at Jefferson Lab will extend the physics potential of the GlueX
detector beyond the main spectroscopy program to perform precision
measurements of various $\eta^{(\prime)}$ decays with emphasis on rare neutral modes.
The physics program of the experiment spans from precision tests of
low-energy QCD to the search for gauge bosons in the mass range below 1 GeV,
coupling the SM sector to the dark sector. Photoproduction of highly
boosted $\eta^{(\prime)}$ mesons using a tagged photon beam with good detection of recoil
protons and multi-photon final states will allow to suppress background and
collect a high-statistics data sample of $\eta$ mesons. All these provide many
advantages over other $\eta^{(\prime)}$ experiments. The JEF
experiment requires to upgrade the inner part of the forward lead glass
calorimeter of the GlueX detector with high-granularity, high-resolution
lead tungstate scintillating crystals. The calorimeter insert is
currently under construction at Jeffeson Lab. The detector will be ready
to take data in 2024. An overview of the JEF project will be presented.
